Curation Trails and Order of Voting

When I was really new to steemit, it came as a surprise to me how someone can have dozens of upvotes (most of insignificant value) in an instant.

Then I learned that is how curation trails work.

Some users choose to follow the upvoting pattern of other users they follow for various purposes, among them to maximize curation rewards or to support certain type of content without actively searching for it. This is how curation trails form. When an account with a curation trail upvotes a post, all the followers in the trail (who have enough voting power) upvote as well.

You can follow a curation trail or create one yourself using the steemauto.com tool.

On SteemAuto, you can set up three important settings for each curation trail you follow:

• your voting weight for each upvote you cast
• if you choose to scale or a fixed voting weight (scale means that if the curator upvotes with a 10% VP and you have the default 50% voting weight, you will upvote with a 5% voting power - that's 10% out of 50%; I don't recommend scaling for accounts with low SP, because your vote will be worthless and you will earn nothing from curation)
• the delay after which you will upvote (after the curator does) - this should be in most cases 0, at least for curators which optimize for curation rewards; should be higher if the curator tends to upvote immediately after the post is published.

You can also choose to enable, disable and re-enable a curation trail at any time.

SteemAuto is probably not the only service which offer the possibility to create and follow curation trails, but it's a well known option.

After quite some time of using the tool for various purposes (I only followed curation trails on my test account), I still have a question which I think can clear up some things.

If two users A and B follow the same curation trail and the curator upvotes, assuming both A and B have enough voting power to upvote, who upvotes first? Or otherwise said, what is the order of upvoting in the curation trail?

The answer is simple if the two users set different delays to their settings for that particular curation trail. Then, the user who set the shortest delay upvotes before the other.

What if both A and B have set the same delay? Who upvotes first, A or B? What is the next factor to consider? The steem power? The potential vote worth (which can be different for the same SP and VP, considering the settings that can be used)? A different factor?

Maybe @mahdiyari, the creator of SteemAuto, can find some time for a quick answer for us? I would appreciate it.